a. Field of the Invention
The present invention relates to a high-altitude working vehicle provided with a vertically and horizontally revolvable and extensible ladder and an operator-carrying lifter movable along said ladder, and more particularly it relates to a safety device for said lifter.
B. Description of the Prior Art
In an extensible ladder vehicle of the type described, a lifter is mounted on the ladder and moved up and down to carry out high-altitude work. In this connection, it should be mentioned that if the ladder is extended or contracted when the lifter is located at positions other than a lowered storage position on the ladder, this is very dangerous. Heretofore, almost no attention has been paid to this point.